Blitz digestive biscuits into fine crumbs using a food processor.
Mix with melted butter until the mixture resembles wet sand.
Press the base into the bottom of a 20cm springform tin and refrigerate for 15 minutes to set.
In a small bowl, bloom gelatine in water for 5 minutes.
In a large bowl, whip cold cream until stiff peaks form. Set aside.
Beat cream cheese until smooth, then add vanilla extract and gradually mix in caster sugar.
Melt white chocolate in a bowl over warm water, then fold into the cream cheese mixture.
Add the bloomed gelatine ( warmed slightly to dissolve) and mix until fully incorporated.
Gently fold in whipped cream until smooth and glossy.
Pour the filling into the chilled tart shell and spread evenly.
Pour raspberry coulis on top and smooth with a spatula.
Garnish with freeze-dried raspberries and grated white chocolate.
Chill for 6-8 hours before serving.